Logarithmic strain measure applied to the nonlinear positional formulation for space truss analysis

The logarithmic strain measure is used to obtain a consistent geometric nonlinear finite element formulation to deal with large strains on space trusses. The formulation is based on the positional formulation and no local system of coordinates on the elements is needed to describe its kinematics. Three numerical examples are presented, including a tensegrity tower and a double layer elastoplastic space truss. The paper proves that the positional nonlinear formulation is valid for other objective strain measures used in the classical nonlinear formulations, i.e. logarithmic strain measure.